farmer



(No Model.)

M. G. FARMER. ELECTRIC LIGHTING APPARATUS.

2 Sheets-Sheet 1.

Patented Feb. 1.4, 18.82.

Unmut .l Il. MANI All N11 T yu-gh (No Model.) 2 sheetssheet 2.

' M. G. FARMER.

ELECTRIC LIGHTING APPARATUS.

Patanted Feb. 14,1882.

UNITED STATES PATENT OFFICE.

MOSES G. FARMER, OF NEWPORT, RHODE ISLAND, ASSIGNOR TO THE UNITED STATES ELECTRIC LIGHTING COMPANY, OF NEW YORK, N. Y.

ELECTRIC LIGHTING APPARATUS.

SPECIFICATION forming part of Letters Patent No. 253,817, dated February 14, 1882.

Application filed March 7, 1881.

To all whom it may concern:

Be it known that I, MosEs G. FARMER., a citizen ofthe United States, residing at Newport, in the county of Newport and State ot' Rhode Island, have invented certain new and useful Improvements in Electric Lighting Apparatus, of which the following is a specification.

My invention relates more particularly to 1o the organization of the incandescent system of lighting by electricity, or that in which a current of electricity is caused to traverse one or more sections ofa conductor, which sections are composed -of some suitable conducting material refractory to heat having a considerably higher resistance per unit of length than the remainder of the circuit, and by means of which resistance a portion of the electricity which traverses the circuit is converted into heat,

zo which,'when of sufcient intensity, produces light.

The object of-my invention is automatically to secure uniformity in the strength of current which traverses one or more circuits in 2 5 which one or more electriclights are included, so that the strength of current shall not be materially affected by any variations that may occur in the -resistances of the illuminating portions of the lights. This end I attain by 3o certain novel combinations of instrumentalities hereinafter specified.

In the accompanying drawings, Figure l is a plan view of so much of an apparatus embodying the subject-matter herein claimed as is 3 5 necessary to illustrate the invention. Fig. 2

is a theoretical diagram, illustrating the. electric circuits and the relation of the different parts of the mechanism to each other.

When heat is developed by the passage of 4o an electric current through a resisting conductor, such as is used in the construction of theincandescentlight,its temperatureincreases in a much more rapid ratio than the increase in the strength of the current. Thus it re- 4 5 quires only about twice the absolute strength of current to fuse a strip of platinum that it does to render it faintly luminous, and the amount of light emitted just below the temperature of fusion is aboutfive times that which (No model.)

would be obtained with a current of seven- 5o eighths of the strength. Vhile therefore a high temperature must be maintained in the incandescent lamp for the salie of economy, it is obvious thataslight variation in the strength of the current at such a temperature will make a very great difference in the amount of light emitted. The object of my regulating apparatus therefore is so to regulate the strength of current as to secure economy as well as uniformity in the light.

Referring to the accompanying figures, one of the main conductors proceeding from the electric generator X (which may be a dynamoelectric machine, a galvanic battery, or other suitable source of electricity) is attached to the binding-screw C4. The current passes thence to the binding-screw C5, through a regulator consisting of an automatically-adjustable rheestat, hereinafter described; thence by the wire o, Figs. l and 2, to the binding-screw C2, 7o Fig. l; and thence by the wire v', dividing at j', jl, and js into three branches, leading respectively to the three lamps L', L2, and L3, these branches again uniting upon a single wire, c2, at the points j4,j5, andj, which wire terminates at the binding-screw C', to which is attached the return main conductor leading to theother pole of the electric generator.

The automatic regulator, which is interposed in the circuit leading from the source of 8o electricity and in the main conductor, (or portion thereof which is common to all the lamps in the system,) may be constructed in various ways, the general principle being that any increase in the normal strength of the current acting upon the regulator shall set in action mechanism acting to diminish said current, while the reverse effect will take place when the strength of the current acting upon the regulator is diminished. One very eifective 9o arrangement which I have devised for this purpose is illustrated theoreticallyin Fig. 2. The principle of this apparatus will be sufficiently well understood by reference to the diagram Fig. 2 in connection with the following de- 95 scription.

A cylinder or roller, G', constructed of nonconducting material, is mounted upon a metallic support, D2. G2 is another cylinder or roller, of metal, of similar size and form, and mounted upon a metallic support, D2. A lieXible conductor, R, of some metal offering cousiderable specific resistance to the passage of an electric current, has one of its ends connected with the axis and metallic support D8 of the non-conducting roller G, and is wound several times around the periphery ot the said roller, (the convolutions being ot' course insulated from each other,) and thence passes across to the metallic roller G2and a number ot' times around its peripheryin the opposite direction. It being premised that one end ofthe iiexible conductor R is electrically connected with the binding-screw G2 and the other with the binding-screw C5, it will be readily understood that the rotation of both rollers G a-nd G2 in such a direction as to wind the conductor from one to the other, as indicated by the arrow, would have the effect of increasing the resistance of the circuit between the points C4 and C2, because the current is obliged to pass through such portion of the whole length of theconductor R as is not in contact with the metallic roller G2. Therefore the greater the portion ofits length thatis wound upon the insulatingroller G and offfrom the metallic roller G2 the greater will be lthe resistance in circuit, and, conversely, the less will it become when the conductor is wound in the opposite direction. The required movement ot' the rollers G and G2 in one direction or the other is preferably effected by means of an independent motor, M5, the particular construction and arrangement of which isimmaterial. Anyknown form of electro-motor (of which the one shown in diagram in Fig. 2 is a type) will serve the purpose well. The electric current for actuating such a motor may he derived from an independent source of electricity, or it may be taken from the main current which supplies the lamps by means of a branch or derived circuit, the former plan being usually preferable. llhe pinion P2 receives its motion from said motor, and is capable of being shifted in one direction or the other, so as to engage with one or the other' of the toothed wheels F F2, which are mounted upon the respective axles of the rollers G and G2. As the electro-motor M5, when in action, always revolves in the same direction, carrying with it the pinion P2, it is obvious that the rollers G and G2 will be caused to rotate in one direction or the other, according as the pinion P2 is engaged with one or the other of the toothed wheels F F2.

I will now explain the mechanism whereby the pinion P2 is shifted and the manner in which this shifting is automatically effected by the increase or decrease of the strength ofthe current in the main conductor.

Referring to Figs. l and 2, M represents a pair of electro-magnetic or magnetizinghelices, which are placed in one of the branch circuits uniting the poles of the generator.

' lmrepresents apa-ir of movable soft-iron cores,

which tend to be drawn into the helices when rendered magnetic by the action of the electric current, the distance which they a re thus drawn dependinguponthestrengthofthecurrent. The movable cores m are attached to one cud of a horizontal beam or lever, B, pivoted at or near its center upon a standard, F, the attractive force of the helices being opposed by the constautforce ofan adjustable antagonistic spring, 2. llhe lever B is capable of a slight oscillatory motion upon its axis, which is limited in each direction by adjustable screw-stops fand b. One pole of a battery or other generator ot' electricity, X, is connected with the standard F by means ot' wire fw', which terminates in a binding-post, C2. The adjustable contactscrew fis connected by ihewircw2 with binding-post C7, and thence by wire 4 with an electromagnet, M3. Similarly, the contact-screw b is connected by the wire w, binding-post C2, and wire 105 with the electro-magnet M2. The electromagnets M: and MAl are connected by wires w7 and in, respectively, with a common binding-post, C2, to which the remaining pole of the generator is connected. This circuit may, if preferred, be supplied with electricity from the main circuit,which supplies the lamps, instead of making use of a separate generator.

It will be understood from the explanation which has been given that as the lever B is deflected from its normal position ot' equilibrium, under the greater or less attraction exerted by the regulating-helices M in opposition to the constant force ot the spring 2, an electric current will be directed through one or the other of the elect-ro magnets M3 M4, as the case may be.

By reference to Fig. 2 it will readily be understood that the electro magnet M3, when in action, will by the force of its attraction throw the pinion P2 into gear with the wheel F, and iu like manner the electro-magnet M will throw the pinion into gear with the wheel F2. Thusif the currentin the main conductor, and consequently that in the several brauch conductors, tends to become too strong, the core m ot' the regulatingmagnet M will be attracted, causing the lever B to make contact with the pointf, thus throwing the electro-magnet M3 into action, which shifts the pinion P2 in such a manner as to cause the motor M5 to interpose a graduaily-increasing re sistance in the circuit, in the manner herein before explained, and thus reduce the strength of the current traversing the regulating-helices l as well as the several branch circuits and lamps, until the attraction in the magnet M becomes sufficiently diminished, when the antagonistic spring 2 will come into yaction and interrupt the contact at f, thus pre- IOO IOS

IIO

drawing the necessary amount of resistance from the main circuit. By this means the current traversing the entire system of main and branch circuits, which includes the lamp or lamps, will be automatically maintained at a practically uniform strength, and this normal strength maybe made greater or less at pleasure by varying the tension of the spring 2 or the position ot' the contact-stopsfand b.

This application constitutes adivision of one tiled by me January 19, 1880, serial No. 965, which exhibits a convenient organization of apparatus for carrying out the objects of my invention. y

I do not herein claim gradually varying the resistance ot' an electric-light circuit, nor the location in a branch circuit of' the regulating' apparatus by which the same is effected, as these constitute the subject-matter of other pending divisions ofthe above-mentioned application. I do not, however, herein limit myself to the specific construction and organization of apparatus shown,as the details of such apparatus may be greatly varied without departing from the principle of my invention.

I claim as my inventionl. The combination, substantially as hereinbet'ore set forth, ot' a rheostat, mechanism for increasing or decreasing the resistance of said rheostat, an electro-magnet included in the same electric circuit with the rheostat, or in a branch thereof, and a lever for controlling the action of said mechanism, which is normally balanced between the attractive force ot' said electro-magnet and a constant antagonistic force, and contact-stops for limiting the motion ot' and determining the action of said lever.

2. The combination, substantially as hereinbefore set iorth, of a generator of electricity, an electric circuit uniting the poles of said generator, one or more electric lamps included in said circuit, an electrounaguet included in said circuit, a lever acted upon in opposite directions by said electro-magnet and by an antagonistic force, electrical contact-stops limiting the motions ol' said lever, reversible mechanism actuated by electricity and controlled by said lever, and haring its motion in one direction or the other determined by the respective preponderance of the opposing forces actingl upon said lever, and mechanism forincreasing and decreasing the current traversing said circuit, which mechanism is controlled by the reversible mechanisln.

In testimony whereofI have hereunto subscribed my name this 3d day of March, A. l). 1881. l

MOSES G. FARMER. Witnesses:

SARAH J. FARMER, DARiUs BAKER. 

